impellor

An impellor, a variant spelling of impeller, is the rotating element of a turbomachinery device that transfers energy between a rotor and a fluid. It is the primary energy-transferring component in many pumps, compressors, and turbines, converting mechanical energy from a motor into fluid kinetic energy and, in the process, increasing the fluid’s pressure.

Construction and design: An impellor typically comprises a central hub, an outer rim, and an array of blades or vanes. Impellers may be enclosed by a casing (closed impeller) or have blades mounted on a hub without a surrounding shroud (open impeller). They are used in axial-flow, radial-flow, and mixed-flow configurations, depending on the fluid direction and the machine’s purpose. Materials vary with operating conditions and may include metals, plastics, and composites.

Operating principle: In centrifugal applications, fluid enters near the center and is accelerated outward by the rotating blades; a diffuser or volute converts much of the generated kinetic energy into static pressure. In axial-flow machines, the impellor imparts momentum along the axis of rotation, producing high-velocity flow with a corresponding pressure rise.

Blade geometry: Blade shapes are commonly described as backward-curved, radial, or forward-curved, with backward-curved designs favored for efficiency and stability in many pumps and compressors.

Applications: Impellors are central to water pumps, HVAC blowers, turbochargers, industrial compressors, and other turbomachinery. The spelling “impellor” is mainly a British English variant; “impeller” is more widely used in American English and modern technical literature.